1996 850 Turbo Misses then stalls after warmup. No codes.

Spadefinger · Post by **Spadefinger** » 05 Oct 2015, 12:11

My '96 850 turbo has been giving me fits lately. I think I may have worked it out, but I've only driven a few miles since the last repair / diagnostic attempt. I'm not entirely sure I am still sane at this point, so any opinions would be welcome.

I knew the PCV system needed changed, though I had ruled it out as a likely cause. So that has been changed and seems to be working as far as I can tell.

I changed the fuel filter next.

The car seemed to run better after the fuel filter switch. I drove about 15 miles, mostly without issue, but there were a few times when it felt like a cylinder wasn't firing.

Went out this morning and it died after about 1 mile or so.

Got it going again, but it was running extremely rough.

I made it home and broke out the compression tester. I had 150 or above on all cylinders after I remembered how to use the gauge properly.

The #2 wire (NGK) was stuck tight and the boot separated from the wire with not all that much force applied. I re-gapped the plugs (fairly new NGK) from .030 to .028, and replaced the #2 wire with an old Bougicord wire from a previous tune up.

Now it seems to be running much better. I have a full set of Bougicord wires on the way as well.

Throughout all this, I never got a single code. That seems odd to me, but I'm new to working on Volvo.
I've checked with 2 different testers, and verified they were working on another vehicle with an active CEL.

Does it make sense that a failing #2 wire would completely stall out the engine? And is it unusual for all this to go on without generating any codes?

Thanks.

Post by **rspi** » 05 Oct 2015, 13:26

Post by **erikv11** » 05 Oct 2015, 19:05

No, a bad #2 wire doesn't add up to the full set of symptoms.

Other issues that would explain all of the symptoms
- Since the PCV was bad previously I would also check that the cam seal inside the distributor is not blown out
- check the cap for arcing and general condition while you are at it
- check the MAF

I think you are right on track with eliminating any possible ignition issues. I can't see any reason to suspect a bad fuel relay given the full content of your post but it is very easy to test with a jumper wire so might as well give that a go too.

Spadefinger · Post by **Spadefinger** » 06 Oct 2015, 08:13

I did not realize how easy the timing belt access was... or how much damage it could cause. Somehow I had missed that second video entirely.

It was definitely the plug wire causing my problems. I inspected the temporary replacement in better lighting this morning and it was obvious that the wire had been arcing against the wall of the spark plug well. It still doesn't feel 100% right, but I've driven about 100 miles since the cord change without incident, and the new wires just arrived.

I thought NGK was a decent brand, but I won't be purchasing their spark plug wires again.

I still wonder at the lack of codes.

Thanks for the replies.

Post by **erikv11** » 06 Oct 2015, 08:20

I just mean there are likely still some other, small problems, it is likely that the plug wire wasn't everything. You can take the #2 plug wire out and run the car all day long, the engine will run rough but will not die.

Spadefinger · Post by **Spadefinger** » 06 Oct 2015, 09:06

I should probably clarify that I think all of the plug wires are of sub-standard quality and are probably from the same batch as the failed wire. I thought NGK was OEM standard for Volvo, but I ordered mine from a third party on Amazon, so maybe they were knock offs.

And I also had the plugs incorrectly gapped. I don't remember where I got .030 in my head, but it was clearly wrong.

I'm learning the hard way not to purchase cheaper aftermarket parts for this thing. Don't get me started about the cheap-o radiator I put in the car. That was ugly.

Thanks again.

Spadefinger · Post by **Spadefinger** » 08 Oct 2015, 15:00

Well, a full set of Bougicord wires seems to have done the trick. The car has never run better since I have had it, and I'm getting about +2 mpg as a bonus.

If this was one of my other cars it would have thrown missfire codes like crazy. Would the lack of codes be a Volvo thing? Or is it possibly an early implementation OBD2 thing? I feel like I'm missing something here.

Post by **erikv11** » 08 Oct 2015, 20:29

I agree this is an odd one, I would have expected P0302 and multiple misfire codes. Glad you got it fixed.